Liquid fuel injector for internal combustion engines



Patented Oct. 26, 1 937 arr QFICE aosaz i LIQUKD FUEL INdECTOR FORHNZTERNAL COMBUSTEGN ENGINES England Application November 13, 1936,Serial No. 110,744

In Great Britain November 13, 1935 6 Claims.

This invention relates to liquid fuel injectors for internal combustionengines, and exclusively to those of the solid injection" type in whicha charge of liquid is injected through a nozzle direct to the workingspace or combustion chamber of the engine without the previous admixtureof air or other gas with said liquid fuel.

It is the primary object of the present invention to provide an improvedconstruction of 19 liquid fuel injector which is particularly robust inuse, and which moreover can be arranged so that the working parts areless delicate than those of the injectors at present'in use.

It is a further object of the invention to pro-- vide an injector havinga valve device, the seating surfaces of which are normally protectedagainst corrosion and overheating, said seating surfaces themselvesbeing more capable of withstanding the constant hammering than those ofthe usual kind.

In a solid injection fuel injector for an internal combustion enginecomprising a body with a fuel passage extending longitudinally thereof,an injection nozzle at the lower end of the body,

a spring, a slidable valve member normally closing said injection nozzleunder the action of the spring but arranged to open automatically whenliquid fuel at high pressure is introduced into the fuel-passage, thepresent invention is character- 39 ized by the fact that a concave valveseat is formed in the lower part of the valve member and coacts with amating convex valve seat surrounding the injection nozzle. Preferablythe concave ,valve seat is of conical shape, and the mating projectionupon the body is in the form of a frusto-cone having an axial bore whichacts as the nozzle.

The invention is illustrated by way of example in the accompanyingdrawing in which Figure 1 is an enlarged sectional elevation showing theconstruction of the lower end of a fuel injector;

Figure 2 is a sectional side elevation to a smaller scale showing acomplete fuel injector. assembly;

Figure 3 is an enlarged sectional view showing the constructionaldetails of the nozzle portion of the injector;

Figure 4 is an enlarged fragmentary section showing diagrammatically amodified arrangemerit of nozzle; and

Figure 5 is a similar view showing a. further modification.

In Figure 1 the body of the injector which can be of any known orsuitable form is indicated at I 0, and is provided with a longitudinalpassage l I through which liquid fuel is normally fed in the directionof the arrow by suitable pressure-producing means, such as a fuelinjection pump.

A valve member 12 is slidably mounted in the 5 body l0, and at its lowerend is formed with a hollow or concave seating l3 conveniently producedby shaping the lower end of the member i2 with a conical recess M. Thishollow seating l3 coacts with a convex seating l5 upon the out- 10 sideof a frusto-conical projection I6 formed upon or carried by the body l0,and this projection is drilled coaxlally at H and 18 so as to producethe usual nozzle through which fuel is injected into the explosionchamber of. the engine. In 5 order to simplify manufacture the lower endof the valve member I2 is reduced in diameter at l9, and the body "I isformed with an annular passage 20 communicating with the longitudinalpassage ll. 20

In use the valve member 12 is normally pressed downwardly convenientlyby means of a spring, and thus the injection nozzle i8 is closed. Whenhigh pressure liquid is introduced into the passage ii, however, it actsupon the two annular 25 surfaces 2! and 22 at the end of the valvememher, and thus lifts the latter, so allowing liquid to pass betweenthe seatings l3 and IE to the injection nozzle Hi. It will be observedthat as normally the injector operates in the vertical 30 position shownin the drawing, the annular recess or well 23 surrounding the projectionit is normally filled with a reserve of liquid fuel, and this not onlytends to cool the injection nozzle but also provides a liquid sealtending to 35 prevent the escape and damaging efiect of hot combustiongases. Moreover, it will be seen that the fuel in passing the seatingsl3 and I5 is rapidly reversed in direction, and it is thought that theturbulence so brought about assists in 40 the breaking-up of the fuelspray.

A constructional example of the invention is shown in Figures 2 and 3,where the body ll) of the injector is provided at its lower end with anannular cap 26 serving to hold a nozzle fitting 5 25 in place. The bodyis drilled axially at 25 for the accommodation of a valve push rod 2?which coacts with a coiled compression spring 28 at its upper end, saidspring in turn being supported by an adjusting screw 29 serving toregulate the force exerted by the spring 28. The screw 29 is drilledaxially for the reception of a feeler rod 30, which in the knownmannerbears against the upper end of the push rod. 21 for giving an 55indication of the manner in which the injector is working.

Fuel under high pressure is fed through a connection 3| whichcommunicates with the iongitudinal passage II, and this in turn connectswith an annular channel 32 and the nozzle-piece 25, as will be seen inFigure 3. A further longitudinal passage 33 in this fitting transmitsthe liquid fuel to the annular space 20, where it acts upon the endsurface 22 of the valve member l2 so as to lift the latter against theaction of the compression spring 28. It will be seen that the upper endof the valve member I 2 is formed with a spigot 34 which cooperates withthe lower end of the push rod 21. The valve member I2 is formed with apair of grooves 35 for the purpose of preventing leakage, and the nozzlefitting 25 is drilled at its lower end with a nozzle passage l8 in theusual manner.

Figure 4 illustrates a further modification in the construction where aplurality of nozzle passages are provided as indicated at 36 in order toprovide a spray effect. Moreover, in the further modification shown inFigure 5, the annular passage 20 is of substantially triangularcrosssection so as to merge with the curved wall of the frusto-conicalprojection l6, thus simplifying the construction of the injector.

It will be understood that the construction of the body portion of thefuel injector may be arranged in many ways other than those illustratedwithout detracting from the advantages derived by the use of theinverted form of valve seating.

What we claim is:

1. A solid injection fuel injector for an internal combustion enginecomprising a body with a fuel passage extending longitudinally thereof,an injection nozzle at the lower end of the body, a spring, a slidablevalve member normally closing said injection nozzle under the action ofthe spring but arranged to open automatically when liquid fuel at highpressure is introduced into the fuel passage, a concave valve seatformed in the lower part of the valve memher and a mating convex valveseating surrounding the injection nozzle.

2. A "solid injection" fuel injector for an internal combustion enginecomprising a body with a fuel passage extending longitudinally thereof,an injection nozzle at the lower end of the body, a spring, a slidablevalve member nor-- mally closing said injection nozzle under the actionof the spring but arranged to open automatically when liquid fuel ,athigh pressure is introduced into the fuel passage, a hollow of conicalshape in the lower end of the valve member, and a projection offrusto-conical form having an axial bore acting as the nozzle, saidhollow in-the valve member being ground so as accurately to fit over thefrusto-conical projection.

3. A solid injection" fuel injector for an internal combustion enginecomprising a body with a fuel passage extending longitudinally thereof,an injection nozzle at the lower end of the body, a spring, a slidablevalve member normally closing said injection nozzle under the action ofthe spring but arranged to open automatically when liquid fuel at highpressure is introduced into the fuel passage, a raised annular valveseat surrounding the nozzle aperture and arranged to slope downwardlyaway therefrom to form an annular well disposed below the level ofnozzle aperture, and a female valve seating within a recess in the endof the valve member adapted to mate with the raised annular seat.

4. A solid injection fuel injector for an internal combustion enginecomprising a body with a fuel passage extending therethrough, aninjection nozzle at the lower end of the body, a spring, a slidablevalve member normally closing said injection nozzle under the action ofthe spring but arranged to open automatically when liquid fuel at highpressure is introduced into the fuel passage, a hollow of conical shapein the lower end of the valve member, and a projection of frusto-conicalform having an axial bore acting as the nozzle, that part of the boredisposed within the projection being of relatively large diameter andthe part disposed below, serving as the nozzle, being of small diameter,said hollow in the valve member being ground so as accurately to fit thefrusto-conical projection.

5. A solid injection fuel injector for an internal combustion enginecomprising a body with a fuel passage extending therethrough, aninjection nozzle at the lower end of the body, a spring, a slidablevalve member normally closing said injection nozzle under the action ofthe spring but arranged to open automatically when liquid fuel at highpressure is introduced into the fuel passage, a hollow in the lower. endof the valve member arranged to serve as a concave seating, a projectioncarried by the body and coacting with the concave seating to control thefiow of fuel into the nozzle, said fuel being caused to flow upwardlybetween the concave seating and the projection before entering thenozzle.

6. A "solid injection fuel injector as claimed in claim 1 in which theconvex valve seat controls the supply of fuel to a plurality of nozzleP8558885.

HENRY JAMES RICHARDS. PERCY WILLIAM CARTER.

